Here's what I'm thinking, and please correct me if I'm wrong. Take the starter out of the fridge 12 hours before making preferment for challah and feed it normally (200 flour, 100 water). Right? 12 hours later, use some for challah, and feed again. Leave at room temperature. 8 hours later feed the starter again, leave at room temperature. 8 hours later, take some starter for the cake, feed the rest, and put back into fridge. The German bread doesn't use starter.

Now, is what I've written sensible? Or should I somehow improve the sequence? I've spaced out baking so that it fit my schedule. The recipes didn't state starter hydration, just said that it should be mature and firm. I'm thinking mine 50% is just fine...Right?

Also, if anyone has any tips for these recipes - I'll be grateful. Thanks!